Aloe vera, a tropical or subtropical plant of the genus Aloe has lance shaped leaves which contain a viscous but essentially clear gel which is given structural rigidity by hairlike connective fibers that run through it. The clear gel of the aloe vera is to be distinguished from the thick, mucilaginous yellow juice that occurs about the base of the plant leaves and adjacent the rind of the leaf. This juice, known as aloin, has been used for many years as an ingredient in many cathartics and purges.
It is known that the therapeutic qualities of the clear gel of aloe vera leaves depend to a large extent on the freshness of the gel. For example, the pain of a jelly fish sting may be stopped not to recur by applying the clear gel from a leaf that has just been cut, but if the gel has been exposed to air and light for about one and a half hours, these powers are greatly diminished if not lost. In some cases, however, relatively old unstabilized gel has been found to be effective and apparently the varying efficacy of a fresh gel for different medicinal purposes reflects the fact that the gel is a complex mixture of substances whose natural stability on exposure to air and light at different temperatures differ from batch to batch.
In addition to loss of therapeutic efficacy on aging, decomposition products occur after a short time that catalyze further decomposition and make the natural gel even less useful than it might be. For example, the commercially available gel extracts are most difficult to compound into cream bases for topical application because the decomposition products tend to bring about a separation of the cream emulsion. Attempts to use the qualities of the gel in cosmetic preparations have been frustrated since such formulations usually become discolored after about a month, adversely affecting their cosmetic utility. In addition to these difficulties, gel that is over three to four weeks old typically becomes rancid and malodorous. At room temperature (about 70 to 80 degrees F.) it may become rancid within twenty-four hours of cutting.
Many of the problems or preserving the medicinal efficacy of the aloe vera gel and stabilizing it for use in cosmetic compositions can be overcome by following the teachings of U.S. Pat. No. 3,892,853 issued July 1, 1975 to Cobble and assigned to Aloe "99" Inc. That patent, entitled "Stabilized Aloe Vera Gel and Preparation of Same" sets forth a process for stabilizing fresh aloe vera gel which results in a product which can be effectively used for many applications. However, it recently has been determined that a very small percentage of users possess an idiosyncratic sensitivity to a portion of the gel product prepared according to the teachings of that reference. When it does occur, such sensitivity is usually noticed when the gel composition is used as a topical preparation for the face of the patient. It is believed that this difficulty is caused, in part, by the difference in the skin chemistry between facial tissue and other epidermal tissue. Thus, an aloe vera gel composition is needed which is stabile and more nearly nonallergenic (hypoallergenic) when used on facial tissue and other sensitive areas of the skin especially since many such patients have failed to respond to any other mode of therapy.